This research involves the continued participation of Rush-Presbyterian-St. Luke's Medical Center in the studies of the Primary Cancer Therapy Group (NSABP). The objectives of the Group are to determine in a systematic fashion whether adjuvant treatment of patients with breast or bowel cancer can affect disease-free survival as well as overall survival, to study the biology of breast cancer, and to determine whether less extensive surgical procedures with or without associated radiation therapy can achieve the same cure rates as more traditional extensive operations. This application seeks funding to continue follow-up of patients already entered into protocols which have completed accrual, to permit continued patient accrual into ongoing protocols, to collect biological material when indicated, and to permit continued intellectual participation of the investigators in this institution in the design, implementation and interpretation of current and future studies. The methods of the study involve the identification of, explanations to and enrollment of eligible patients in the current protocols of the NSABP. These include segmental mastectomy with or without radiation therapy vs. total mastectomy, L-PAM, and 5-fluorouracil with or without Adriamycin in patients with Stage II breast cancer (with Tamoxifen added in those who are estrogen receptor positive), sequential methotrexate and 5-fluorouracil vs. no treatment in Stage I estrogen receptor negative patients, and Tamoxifen vs. placebo in Stage I estrogen receptor positive patients. The colon protocols include registration of patients with Duke's A and D tumors, and 3 drugs vs. BCG vs. surgery alone in patients with Duke's B and C disease.